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Biomedical subjects

L W Cai

Publications and source records attributed to L W Cai.

13 recordsLinked to original sources

[Purification of recombinant hEGF expressed in yeast Pichia pastoris and the study on its characters].

OBJECTIVE: To obtain recombinant human epidermal growth factor(hEGF) that can be used in animal experiments and clinical trial. METHOD: Chemically synthesized hEGF gene was expressed in Yeast Pichia pastoris and the secretory hEGF was purified by Phenysepharose 6 Fast Flow(high sub), Q-sepharose High Performance, and Superdex 30 chromatography, and its characters were studied by respective methods. RESULTS: The purified hEGF doesn't contain pyrogen, endotoxin, or yeast chromosome DNA and the purity reached 98%. The recombinant human EGF has correct molecular weight, pI, N-terminal amino acids sequences, peptide map, ultraviolet spectrum and well-biological activity. CONCLUSION: The purified hEGF is in accord with the requirements for animal experiments and clinical trial which provides the basis of preparing EGF agents for clinical test.

Animals↗

[The basic and applied study on the epidermal growth factor].

This article reviews the results of the basic research about epidermal growth factor and its receptor, and the development of the novel drug, EGF eyedrop, that containing chemically synthesized EGF gene, the construction of EGF expression vector, the transformation of the host cells, the purification of the recombinant protein EGF, the preparation of three batches of the EGF product and identification, the preclinical and clinical trials. Relevant studies show that recombinant EGF consisting of 51 amino acids can be secreted into the medium under the control of the alpha factor leading sequence in the yeast cells. The EGF can accelerate the growth of corneal-limbal epithelial cells and the healing of an alkali burned corneal. The EGF can be used in curing oral cavity ulcer and skin burned wound. And it has the preventive effects on experimental duodenal ulcer of rat. The antiserum was made for test of the concentration of blood EGF and urine EGF by RIA. Data from studies demonstrate the inhibition effect of EGF on the growth of tumor cells, such as A431 and BT325 cells in the presence of high EGF concentration (> 10 ng/ml). The expression of EGFR and DNA ploidy in renal carcinoma has clinical significance. Crystallization and preliminary x-ray diffraction studies of the EGF has been made. The MW of the EGF product is 6000, and the pI is about 4.6 and it has correct N-terminal amino acids sequences, immunogenicity and biological activity. There is no vestige of the DNA of the yeast cells. Animal experiments reveal that there is no cumulation of the EGF in the body, and EGF can promote corneal epithelial healing. There is no toxicological effect during cornea wound healing of rabbit. A randomized, double-blind, placebo-controlled, multi-center clinical trial was conducted in four hospitals to assess safety, ocular tolerance and efficacy of an ophthalmic solution of EGF for 200 cases of cornea transplantation and 247 cases of nebulae. Unequivocal results were obtained as the eyedrop really accelerate the wounded cornea healing. So, the EGF eyedrop as a novel drug of class I is approved by the National Drug Administration, and this is the first gene engineering drug that come from yeast expression system in China.

Animals↗

[Progress in the study of nerve growth factor family and its receptors].

There were several noticeable progress in the study of the neurotrophic factors, their receptors and the neuronal apoptosis. Firstly, several members of the nerve growth factor family have been identified: NGF, BDNF, NT-3 and NT-4/5. Secondly, the relationship between the three-dimensional structure of the NGF and its function and evolution has been revealed. Thirdly, two kinds of the neurotrophin family receptors were characterized, they are low-affinity NGFR (p75 NGFR) and the trk proto-oncogene product such as p140trkA, p145trkB and p145trkC. Induction of apoptosis by the low-affinity NGFR was also found. Finaly it is possible to use the neurotrophin for treating the degenerative neurological illnesses.

Amino Acid Sequence↗

Determination of the complete nucleotide sequence of HBV adr NC-1 DNA.

On the basis of sequencing the large DNA-fragments which have been inserted into M13mp8, we design a simple strategy to determine the complete nucleotide sequence of HBV adr NC-1 DNA with chain termination method. The whole genome is 3195 nucleotides long. Five reading frames are observed. The gene location and organization are shown.

Base Sequence↗